Method of making corrugated flexible hose



May 20, 1969 c. H. OSBORN 3,445,308

METHOD OF MAKING CORRUGATED FLEXIBLE HOSE Original Filed June 8, 1964Sheet of 2 FIG-215 I INVENTOR. CARROLL H. OSBORN ATTORNEY May 20, 1969c. H. OSBORN 3,445,308,

METHOD OF MAKING CORRUGATED FLEXIBLE HOSE Original Filed June 8, 1964Sheet of 2 INVENTOR. CARROLL H. OSBORN M w/w/v ATTORNEY United StatesPatent 3,445,308 METHOD OF MAKING CORRUGATED FLEXIBLE HOSE Carroll H.Osborn, Waynesville, N.C., assignor to Dayco Corporation, a corporationof Delaware Original application June 8, 1964, Ser. No. 373,257, nowPatent No. 3,329,172, dated July 4, 1967. Divided and this applicationJan. 10, 1967, Ser. No. 627,571

Int. Cl. B29c 17/00 US. Cl. 156-86 4 Claims ABSTRACT OF THE DISCLOSURE Amethod of manufacturing corrugated hose including the steps of coating aheat-shrinkable cord with an elastomer, forming this coated cord into ahelical reinforc ing coil, and placing an elastomeric tube over thecoil. The tube is shrunk over the body to create corrugations andsubsequent heat is applied to cause the cord to shrink and cut throughthe coating, thus leaving the coating in an arcuate shape to create thefinal reinforcing mem- 'ber.

This application is a division of US. application Ser. No. 373,257,filed June 8, 1964, now US. Patent No. 3,329,172.

This invention relates to a hose for conveying fluids such as air, andthe method of manufacturing same. More particularly, the inventionrelates to a fluid-impervious hose containing a radial reinforcement towithstand pressure and prevent collapse when used in low pressure vacuumsystems, oxygen systems, hair dryers, respirating devices, and the like.

The type of hose referred to herein usually comprises an elastomericflexible tube which is reinforced against radial collapse by areinforcing member comprising axially spaced helical coils extendingthroughout its length. While the hose of the present invention may bemade or constructed by any of several different methods, the preferredform of the invention will refer to a hose which is similar inconstruction to those more fully described in United States Patents Nos.2,766,806, 2,780,803, and 2,822,857, of common assignment. This is thetype of hose which has found wide acceptance because of its lightnessand strength, and the fact that it is sufiiciently flexible to permitbending and yet impervious to leakage of fluid. At the same time, theuse of the reinforcing coil will prevent collapse of the tube. Theabove-described hose has an outer tubular member made of a thermoplasticmaterial such as polyvinyl chloride, or other vinyl polymers orcopolymers, or the polyolefins such as polyethylene or polypropylene. Ifdesired, the outer tubular member may consist of a blend of thesematerials or may include these materials blended with synthetic ornatural rubbers. In the conventional hose of this type the reinforcingmember usually consists of a steel wire which has been coated with anelastomeric material similar to that of the tubular member and formedinto the reinforcing member referred to above.

The hose of the present invention represents an improvement over theprior art in providing hose of the type generally described above exceptthat it utilizes a reinforcing member which is considerably lighter inweight than the conventional wire reinforcing member. Lighter weighthose creates a number of advantages; for example, when using such a hosein a household type hair dryer the hair dryer bonnet attached to thehose has less tendency to be displaced from the head by head movementsthan would occur with a conventional hose. When such a hose is used forother purposes, such as 3,445,308 Patented May 20, 1969 vacuum cleaners,it reduces the amount of weight which must be carried around by theuser.

In addition to the lightness of weight, the hose provided by the presentinvention presents an additional advantage in that it eliminates anymetallic substance from the finished hose. This may be an importantfactor in certain uses where there is a possibility of accidentalelectrical conduction, or burns which might be received throughaccidental exposure to induction heating.

According to the present invention the above hose may be manufactured ina very simple manner, and yet the final product is one which has greatutility, particularly where lightness of weight is extremely important.

It is, therefore, a primary object of the present invention to provide afluid-impervious noncollapsible hose which is reinforced against radialcompression.

It is an additional object of this invention to provide such a hosewhich is extremely light in weight.

It is still another object of the invention to provide a simple methodof manufacturing such a hose.

These and other objects will be apparent in the following specification,claims, and drawings, in which:

FIGURE 1 is an elevational view in partial cross section illustratingthe first step in the manufacture of the hose.

FIGURE 2 is an enlarged sectional view of a portion of the novel hoseduring a later stage of construction.

FIGURE 3 is a perspective view partially broken away to illustrate thepositioning of the hose during a subsequent step in the construction.

FIGURES 4 and 5 are perspective views illustrating further steps in theconstruction of the hose.

FIGURE 6 is an enlarged sectional view of a portion of the hose duringthe last step of the construction which occurs as shown in FIGURE 5.

FIGURE 7 is a perspective view in partial section illustrating thefinished hose.

Referring now to the drawings and particularly to FIGURE 1, referencenumeral 11 designates a reinforcing member consisting of axially spacedhelical coils. The construction of this reinforcing member will bedescribed below. This member 11 has been subjected to a spring windingoperation whereby the helical configuration is obtained and in which theturns of the coils of the reinforcing member are approximately equallyspaced in an axial direction. This reinforcing member is placed upon amandrel .12 which consists of a cylindrical member, usually steel, uponwhich the hose is built. The mandrel and reinforcing member are placedwithin a vacuum box 13 which consists of a hollow cylindrical memberhaving an opening 14 which is connected to an external vacuum pump inorder to evacuate the interior of the vacuum box. A tubular member 15has previously been inserted within the vacuum box and the ends cuffedover the wall of the vacuum box as shown in FIGURE 1. With thisrelationship, evacuation of air from the vacuum box by means of theopening 14 will cause the tubular member 15 to expand against the innersurface of the vacuum box. The tubular member 15 is preferably ofthermoplastic material such as polyvinyl chloride, other vinyl polymersor copolymers, or polyolefins such as polyethylene or copolymers. Suchmaterials have an excellent elastic memory and therefore may be easilyexpanded to the position shown and subsequently returned to the originaldiameter. The tubular member is preferably formed by extrusion, asdescribed in the abovementioned patents.

After insertion of the mandrel and reinforcing member within the vacuumbox having the expanded tubular member 15, the vacuum is releasedtherefore allowing the member 15 to again contract to its originaldiameter upon the mandrel and to surmount the coils of the reinforcingmember 11. This process is more fully described in the above-referencedpatents, but is also illustrated in the enlarged showing of FIGURE 2 inwhich the relationship between the outer tubular member, the reinforcingmember, and the mandrel is clearly seen.

As shown in FIGURE 2, the reinforcing member 11 consists of a centralmember 17 and an outer coating 16. While in the prior art the centralmember would normally be a steel wire, the present invention providesfor this to be of an entirely different material and to embody anentirely different concept. In the present application this member 17 isa nylon or polypropylene monofilament cord, preferably about .030 inchin diameter, but may be a cord of some other material, which is alsoheat shrinkable, such as fiber glass filaments which have been twistedinto a single cord of approximately the same diameter. The nylon orglass fiber cord has been coated by the material 16 which is preferablypolyvinyl chloride, but may be any of the other materials used for theouter tubular member 15. The preferable form of the invention requiresthat the coating 16 be similar to the tubular member 15. After coating,the assembly of cord 17 and coating 16 is approximately .060 inch indiameter.

The next step of the invention is illustrated in FIG- URE 3 in which theassembly of the reinforcing tubular member and the mandrel has beenplaced within a heated chamber 18. The assembly of the tubular memberand reinforcing member is designated by reference numeral 19. Mountedwithin the heating chamber 18 are supports 20 and 21 upon which theshafts of the mandrel may be supported during heating. The mandrel 12has a hollow interior and to one end is attached a pipe 22 which leadsto a source of vacuum 23. The heating chamber is preferably a hot aircuring oven, such as more fully described in the above patents, andcapable of creating sufficient temperature to soften the plasticmaterials used for the construction of the hose. For example, when usingpolyvinyl chloride for the tubular member 15 and the coating material16, a temperature of 300 F. plus or minus F. is found to producesatisfactory results. It should be noted that the use of a chamber ofthis nature is not essential, as it is also possible to heat theassembly by means of infrared lamps or other conventional methods.However, the softening temperature is imposed upon the assembly 19 andwhen this occurs the tubular member and the coating material 16 are atthe point of plastic flow so that they may be bonded to each other overselected areas, which may be predetermined by the exact temperatures andvacuum pressures which are imposed. At this point vacuum is applied tothe pipe 22 from the outside source 23 and simultaneously to theinterior of the mandrel 12. By means of a series of apertures 26 in themandrel the same vacuum is applied within the tubular member 15 so thatit is pulled radially inward to create the required convoluted shape.The combination of the radially inward pressure created by the vacuumand the condition of plastic flow will create a bond between the coatingand the outer tubular member. As a next step the assembly will becooled, which may be done by several methods; for example, the supply ofheat may be shut off to the heating chamber and the assembly may beallowed to cool naturally, or cooling air may be circulated within thechamber to hasten this process. The vacuum may be retained or may bereleased depending on the amount of bonding which is desired. It is alsopossible to cool the assembly by removing it from the chamber andplacing it under cold water or other cooling medium. It is also feasibleto eliminate the vacuum drawing process just described, and to allow theelastic memory of the tubular member to create a temporary bond betweenthe tubular member and the helical coils. The step of heating aspreviously described will then create the permanent bond and shrinkageof the cord as before, followed by the steps previously described.

When the cooling is completed, the hose assembly 19 is stripped from themandrel 12 as shown in FIGURE 4 by pulling it off by hand; oralternatively, by using a simple mechanical stripping device. During theheating and cooling process the cord 17 has shrunk, causing it to splitout of its coating and to assume the position designated in FIGURE 6 bycord 17a and coating 16a. Because of the shrinkage, there is a more orless consistent inward radial motion of the cord 17 throughout itslength so that it has cut completely through the inner surface of thecoating. By grasping one end of the cord 17 the operator may then verysimply pull out the entire member as shown in FIGURE 5; this member willtend to be pulled further inward as shown by the cord designated as 17band the coating 16b of FIGURE 6. As a result, the coating 16 will thenhave an arcuate configuration formed by the inward ends 24 and 25 whichdefine an inwardly extending loop or open portion 27. The outer surfaceof the coating conforms to the outwardly extending corrugations 28 ofthe tubular member 15, while the corrugations 29 of the member 15 extendinwardly between the turns of the helical member. The resultant coatedmember 16 thus provides the sole helical reinforcement for the finalassembly and has an arcuate configuration, the outer surface thereofbeing bonded to the inner surface of the tubular member 16. It should benoted that the portion of the hose shown in FIGURE 6 is shown insomewhat extended state because of the slight tension created by pullingfree the cord 17. In a relaxed condition, however, the hose 19 willappear as shown in FIGURE 7, in which the inner convolutions of thetubular member 15 extend nearly to the inner plane of the coated member16. The resultant product is one having a continuous reinforcing memberwhich provides resistance to radial forces and yet is considerablylighter than prior art hose because of the absence of any centralreinforcing member.

While the invention has been described above with reference tomanufacturing the hose by the use of a preformed tubular member, itshould be noted that the invention specifically contemplates theformation of the hose initially by other methods. For example, a stripconsisting of a plastic material and a cord, such as the cord 17 in thepresent invention, may be extruded and spirally overlapped by the methoddescribed in United States Patent No. 2,798,508. Subsequently, the sameprocess as described above will take place, causing the cord to bestripped from the final assembly. It is also possible to form acontinuous hose by extruding the outer tubular member over the cord 17as shown, for example, in United States Patent No. 2,963,749, thensubsequently stripping out the cord by the method described above. Theessential principle of manufacture and the final product involve theconcept of creating a reinforcing member which is light in weightcompared to the prior art products. Other variations in method ofmanufacture and in the finished product are contemplated as being Withinthe scope of the present invention.

What is claimed is:

1. A method of manufacturing corrugated flexible hose comprising thesteps of coating a heat-shrinkable cord with an elastomeric material,forming said coated cord into a reinforcing member having axially spacedhelical coils, surmounting said member with an elastomeric body to forma hose assembly, contracting said body over said coils to createcorrugations conforming to said coils, and subjecting said assembly tosufiicient heat to cause said cord to shrink radially inward and cutthrough said coating material, said shrinkage creating an arcuateconfiguration in said coating material corresponding to saidcorrugations.

2. The method of claim 1 in which said cord is nylon.

3. The method of claim 1 in which said cord is composed of twisted glassfiber filaments.

4. A method of manufacturing corrugated flexible hose comprising thesteps of coating 21 heat-shrinkable cord with an elastomeric material,forming said coated cord into a reinforcing member having axially spacedhelical coils, surmounting said member with an elastomeric body to forma hose assembly, contracting said body over said coils to createcorrugations conforming to said coils, bonding said body to said memberto form an assembly thereof, shrinking said cord radially inward andcutting through said coating material, and removing said cord to formsaid coating material into coils having an arcuate cross section with aninwardly extending open portion and an outwardly extending closed loopportion, said corrugations conforming to said closed loop portion.

References Cited UNITED STATES PATENTS 3,296,047 1/1967 Parr 156143 XR3,105,492 10/1963 Jeckel 138122 XR 2,949,133 8/ 1960 Rothermel et al.

FOREIGN PATENTS 453,303 9/1936 Great Britain.

10 PHILIP DIER, Primary Examiner.

US. Cl. X.R.

